Multi-band radio frequency power amplifier based on coupling line

Abstract

The invention discloses a multi-band radio frequency power amplifier based on a coupling line. The multi-band radio frequency power amplifier comprises a multi-passband filter type input matching network, a multi-band gate bias circuit, a field effect transistor, a multi-band drain bias circuit and an ultra-wideband output matching network, the adopted multi-passband filter type input matching network can support a plurality of different working frequencies at the same time, so that the circuit area and the design and manufacturing cost are greatly reduced, and the integration level is improved; in the traditional technology, interconnection loss between devices can be increased and performance degradation of output power and output efficiency can be caused by cooperative use of a plurality of single-frequency power amplifiers, however, by adopting an integrated design, compatibility of different frequency bands is better, circuits are simpler, loss is lower, and higher output power and efficiency can be ensured. Furthermore, by utilizing the capacitive coupling characteristic of a coupling line in the multi-passband filter type input matching network, a blocking capacitor can not be used for isolating a direct current signal in the input matching network, and the design complexity is lower.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency and microwave, and particularly relates to a multi-band radio frequency power amplifier based on coupled lines. Background Art

[0002] With the rapid development of wireless communication technology, different frequency bands have been developed and allocated successively, resulting in the coexistence of multiple communication frequency bands. This requires that wireless communication systems be compatible with multiple communication frequency bands. The traditional approach is to use wireless communication devices with different operating frequency bands in combination, but this will increase the number of devices in the communication system, making the communication system more bulky and complex, reducing system stability and increasing design and manufacturing costs. In recent years, there have also been efforts to solve this multi-communication frequency band compatibility problem by developing broadband or ultra-wideband communication devices that cover multiple communication frequency bands. However, for broadband or ultra-wideband devices, adjacent band signals are prone to interference with each other, reducing system performance. Therefore, it is particularly important to develop multi-passband devices that can be compatible with multiple communication frequency bands. As a key module in the transmitter of a communication system, the design and development of a power amplifier that supports multiple communication frequency bands is of great significance for improving the multi-communication frequency band compatibility of wireless communication systems.

[0003] Although there have been studies on multi-band power amplifiers, they mainly support dual-band or triple-band, and there are few reports on power amplifiers that support four bands and more bands. However, currently, there are more than three commercial communication frequency bands, so it is particularly important to study power amplifiers that support four bands and more bands. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a multi-band radio frequency power amplifier based on coupled lines. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0005] The present invention provides a multi-band radio frequency power amplifier based on coupled lines, comprising:

[0006] a multi-passband filter type input matching network, a multi-band gate bias circuit, a field effect transistor, a multi-band drain bias circuit, and an ultra-wideband output matching network; wherein,

[0007] the multi-passband filter type input matching network is used to screen the input signal, allow signals within a preset frequency band to pass through, and perform impedance matching, and send the signals within the preset frequency band to the field effect transistor;

[0008] the multi-band gate bias circuit is used to provide a gate DC bias voltage for the gate of the field effect transistor;

[0009] the field effect transistor is used to amplify the signals within the preset frequency band and output the amplified signals;

[0010] The multi - band drain bias circuit is used to provide a drain DC bias voltage for the drain of the field - effect transistor;

[0011] The ultra - wideband output matching network is used to perform impedance matching between the output end and the load and output the amplified signal.

[0012] In an embodiment of the present invention, the multi - passband filter - type input matching network is composed of coupled lines and M microstrip lines connected in series according to the operating frequency band, where M is a positive integer greater than or equal to 2. Among them, the input end of the multi - passband filter - type input matching network serves as the input end of the multi - band radio - frequency power amplifier.

[0013] In an embodiment of the present invention, the multi - band gate bias circuit is composed of Q microstrip lines connected in series, and capacitors grounded are connected in parallel between adjacent microstrip lines, where Q is a positive integer greater than or equal to 2.

[0014] In an embodiment of the present invention, the input end of the multi - band gate bias circuit serves as the gate DC power input end of the multi - band radio - frequency power amplifier, a gate voltage Vgs is connected, and the output end is connected to the bias end of the multi - passband filter - type input matching network.

[0015] In an embodiment of the present invention, the multi - band radio - frequency power amplifier further includes: an RC stabilization network; the RC stabilization network suppresses high - frequency oscillations in the signals within a preset frequency band and outputs the suppressed signals to the field - effect transistor.

[0016] In an embodiment of the present invention, the RC stabilization network is composed of a resistor R and a capacitor C3 connected in parallel.

[0017] In an embodiment of the present invention, the source of the field - effect transistor is grounded, the gate is connected to the output end of the multi - passband filter - type input matching network, and the drain is respectively connected to the output end of the multi - band drain bias circuit and the input end of the ultra - wideband output matching network.

[0018] In an embodiment of the present invention, the multi - band drain bias circuit is composed of X microstrip lines connected in series, and capacitors grounded are connected in parallel between adjacent microstrip lines, where X is a positive integer greater than or equal to 2.

[0019] In an embodiment of the present invention, the input end of the multi - band drain bias circuit serves as the drain DC power input end of the multi - band radio - frequency power amplifier, a drain voltage Vds is connected, and the output end is connected to the drain of the field - effect transistor.

[0020] In an embodiment of the present invention, the ultra - wideband output matching network is composed of P microstrip lines and a capacitor C7 connected in series, where P is a positive integer greater than or equal to 2.

[0021] Advantages of the present invention:

[0022] In the solution provided by the present invention, the multi-band filter type input matching network can support multiple different operating frequencies simultaneously, eliminating the need for multiple single-frequency power amplifiers to be used in combination. This significantly reduces the circuit area and design and manufacturing costs, and improves the integration level. In the traditional technology, the use of multiple single-frequency power amplifiers in combination increases the interconnection loss between devices, resulting in performance degradation of the output power and output efficiency. However, through the integrated design of the present invention, better compatibility between different frequency bands, simpler circuits, and lower losses can be achieved, ensuring higher output power and efficiency. Further, by utilizing the capacitive coupling characteristics of the coupled lines in the multi-band filter type input matching network, a DC blocking capacitor can be omitted in the input matching network, thus reducing the design complexity. Description of the drawings

[0023] Figure 1 Schematic diagram of the structure of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention;

[0024] Figure 2 Layout of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention;

[0025] Figure 3 Simulation curve diagram of return loss and small-signal gain of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention;

[0026] Figure 4 Curve diagram of gain and power added efficiency of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention when operating at 0.75 GHz;

[0027] Figure 5 Curve diagram of gain and power added efficiency of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention when operating at 2.6 GHz;

[0028] Figure 6 Curve diagram of gain and power added efficiency of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention when operating at 3.6 GHz;

[0029] Figure 7 Curve diagram of gain and power added efficiency of a multi-band RF power amplifier based on coupled lines provided by an embodiment of the present invention when operating at 4.9 GHz. Detailed implementation manners

[0030] The following further describes the present invention in detail with reference to specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0031] An embodiment of the present invention provides a multi-band radio frequency power amplifier based on coupled lines, as Figure 1 shown, which may include:

[0032] A multi-passband filter type input matching network, a multi-band gate bias circuit, a field effect transistor, a multi-band drain bias circuit, and an ultra-wideband output matching network; wherein,

[0033] The multi-passband filter type input matching network is used to screen the input signal, allow the signal within a preset frequency band to pass through, and perform impedance matching, and send the signal within the preset frequency band to the field effect transistor;

[0034] The multi-band gate bias circuit is used to provide a gate DC bias voltage to the gate of the field effect transistor;

[0035] The field effect transistor is used to amplify the signal within the preset frequency band and output the amplified signal;

[0036] The multi-band drain bias circuit is used to provide a drain DC bias voltage to the drain of the field effect transistor;

[0037] The ultra-wideband output matching network is used to perform impedance matching between the output end and the load and output the amplified signal.

[0038] The multi-passband filter type input matching network adopted in the embodiment of the present invention can support multiple different operating frequencies simultaneously, without the need for multiple single-frequency power amplifiers to cooperate, greatly reducing the circuit area and design and manufacturing costs, and improving the integration degree; in the traditional technology, the use of multiple single-frequency power amplifiers in cooperation will increase the interconnection loss between devices, resulting in performance attenuation of the output power and output efficiency, while the present invention adopts an integrated design, making the compatibility of different frequency bands better, the circuit simpler, and the loss lower, and can ensure higher output power and efficiency.

[0039] For the convenience of understanding, the following takes a multi-band radio frequency power amplifier with a frequency band of 4 as an example for specific introduction.

[0040] The multi-passband filter type input matching network is composed of coupled lines and M microstrip lines connected in series according to the operating frequency band, where M is a positive integer greater than or equal to 2. Among them, the input end of the multi-passband filter type input matching network serves as the input end of the multi-band radio frequency power amplifier.

[0041] Taking M as 9 as an example, the multi-passband filter type input matching network may include:

[0042] Coupled line CL1, microstrip lines TL1, TL2, TL3, TL4, TL5, TL6, TL7, TL8, and TL9; where

[0043] The first end of microstrip line TL1 serves as the input end of the multi-passband filter type input matching network, and the second end is connected to the first end of microstrip line TL2;

[0044] The second end of microstrip line TL2 is connected to the first end of microstrip line TL3;

[0045] The second end of microstrip line TL3 is connected to the input end of coupled line CL1;

[0046] The output end of coupled line CL1 is connected to the first end of microstrip line TL4, the coupling end is connected to the first end of microstrip line TL5, and the isolation end is connected to the first end of microstrip line TL6;

[0047] The second end of microstrip line TL6 is connected to the first end of microstrip line TL7;

[0048] The second end of microstrip line TL7 is connected to the first end of microstrip line TL8;

[0049] The second end of microstrip line TL8 is connected to the first end of microstrip line TL9;

[0050] The second end of microstrip line TL9 serves as the output end of the multi-passband filter type input matching network.

[0051] The multi-passband filter type input matching network has the characteristic of achieving impedance matching in decibels within N frequency bands, where N is a positive integer greater than or equal to 2.

[0052] The multi-passband filter type input matching network can screen the passage of signals in N frequency bands, that is, allow signals within each preset frequency band to pass, while not allowing signals outside the preset frequency to pass, and at the same time complete impedance matching. The multi-passband filter type input matching network realizes input impedance matching within multiple discrete target frequency bands, ensuring the efficient transmission of radio frequency signals to the amplifier input end and reducing reflection loss. By selectively matching specific frequency bands through the filter structure, the multi-band performance is improved.

[0053] The multi-band gate bias circuit is composed of Q microstrip lines connected in series, and capacitors grounded are connected in parallel between adjacent microstrip lines, where Q is a positive integer greater than or equal to 2.

[0054] The input end of the multi-band gate bias circuit serves as the gate DC power input end of the multi-band radio frequency power amplifier, connects to the gate voltage Vgs, and the output end is connected to the bias end of the multi-passband filter type input matching network.

[0055] Taking Q as 3, the multi-band gate bias circuit may include:

[0056] Microstrip line TL10, microstrip line TL11, microstrip line TL12, capacitor C1 and capacitor C2; wherein,

[0057] The first end of the microstrip line TL10 serves as the input end of the multi-band gate bias circuit, and the second end is connected to the first end of the microstrip line TL11;

[0058] The second end of the microstrip line TL11 is connected to the first end of the microstrip line TL12;

[0059] The second end of the microstrip line TL12 serves as the output end of the multi-band gate bias circuit;

[0060] The first end of the capacitor C1 is connected to the second end of the microstrip line TL10, and the second end is grounded;

[0061] The first end of the capacitor C2 is connected to the second end of the microstrip line TL11, and the second end is grounded.

[0062] The second end of the microstrip line TL12 serves as the output end of the multi-band gate bias circuit and is connected to the second end of the microstrip line TL7 in the multi-passband filter type input matching network.

[0063] The multi-band gate bias circuit provides a DC bias voltage for the gate of the field effect transistor, and has the function of allowing DC signals to pass through while not allowing AC signals to pass through, preventing RF leakage.

[0064] The source of the field effect transistor is grounded, the gate is connected to the output end of the multi-passband filter type input matching network, and the drain is respectively connected to the output end of the multi-band drain bias circuit and the input end of the ultra-wideband output matching network.

[0065] In the multi-band RF power amplifier proposed by the embodiment of the present invention, the field effect transistor may use the field effect transistor CG2H40010F of Cree Semiconductor Company as the core power device.

[0066] The field effect transistor amplifies the AC signals within N frequency bands, converting DC power into AC power. As the core component of the amplifier, the field effect transistor converts the input small signal into a high-power signal. Its transconductance, gain and linearity directly affect the output performance of the amplifier.

[0067] The multi-band drain bias circuit is composed of X sections of microstrip lines connected in series, and capacitors grounded are connected in parallel between adjacent microstrip lines, where X is a positive integer greater than or equal to 2.

[0068] The input terminal of the multi-band drain bias circuit serves as the DC power supply input terminal for the drain of the multi-band RF power amplifier, and is connected to the drain voltage Vds. The output terminal is connected to the drain of the field effect transistor.

[0069] Taking X as 4, the multi-band drain bias circuit may include:

[0070] Microstrip line TL13, microstrip line TL14, microstrip line TL15, microstrip line TL16, capacitor C4, capacitor C5, and capacitor C6; where

[0071] The first end of the microstrip line TL13 serves as the input terminal of the multi-band drain bias circuit, and the second end is connected to the first end of the microstrip line TL14;

[0072] The second end of the microstrip line TL14 is connected to the first end of the microstrip line TL15;

[0073] The second end of the microstrip line TL15 is connected to the first end of the microstrip line TL16;

[0074] The second end of the microstrip line TL16 serves as the output terminal of the multi-band drain bias circuit and is connected to the drain of the field effect transistor;

[0075] The first end of the capacitor C4 is connected to the second end of the microstrip line TL13, and the second end is grounded;

[0076] The first end of the capacitor C5 is connected to the second end of the microstrip line TL14, and the second end is grounded;

[0077] The first end of the capacitor C6 is connected to the second end of the microstrip line TL15, and the second end is grounded.

[0078] The multi-band drain bias circuit provides a DC bias voltage for the drain of the field effect transistor, and has the function of allowing DC signals to pass through while not allowing AC signals to pass through.

[0079] The ultra-wideband output matching network can be composed of P sections of microstrip lines and capacitor C7 connected in series, where P is a positive integer greater than or equal to 2.

[0080] Taking P as 3, the ultra-wideband output matching network may include:

[0081] Microstrip line TL17, microstrip line TL18, microstrip line TL19, and capacitor C7; where

[0082] The first end of the microstrip line TL17 serves as the input terminal of the ultra-wideband output matching network, and the second end is connected to the first end of the microstrip line TL18;

[0083] The second end of the microstrip line TL18 is connected to the first end of the capacitor C7;

[0084] The second end of capacitor C7 is connected to the first end of microstrip line TL19;

[0085] The second end of microstrip line TL19 serves as the output end of the ultra-wideband output matching network.

[0086] It can be understood that for a multi-band radio frequency power amplifier, the output end of the ultra-wideband output matching network is the output end of the multi-band radio frequency power amplifier.

[0087] The ultra-wideband output matching network realizes impedance matching. The frequency band of the ultra-wideband covers all N frequency bands, improves the overall working efficiency of the circuit, and reduces the reflection loss; it realizes the impedance matching between the output end and the load (such as an antenna) within a wide frequency band to ensure the efficient transmission of the amplified signal. Compared with the multi-passband design, the ultra-wideband structure covers continuous frequency bands and simplifies the complexity of multi-band output matching.

[0088] The multi-band radio frequency power amplifier may further include: an RC stabilization network; the RC stabilization network suppresses high-frequency oscillations in the signals within a preset frequency band and outputs the suppressed signals to the field-effect transistor.

[0089] In practical applications, in the face of some scenarios with unstable signals, an RC stabilization network can be selected to be introduced into the multi-band radio frequency power amplifier, and the RC stabilization network is arranged between the output end of the multi-passband filter type input matching network and the gate of the field-effect transistor. The RC stabilization network can be composed of a parallel resistor R and capacitor C3.

[0090] The RC stabilization network makes the stability factor K of the multi-band radio frequency power amplifier greater than 1 within N frequency bands, that is, makes the radio frequency power amplifier stable within N frequency bands. By absorbing or attenuating the energy of unstable frequencies, it prevents self-excited oscillation, especially enhances the reliability during multi-band interaction, suppresses potential high-frequency oscillations, and improves the circuit stability. It can be understood that in a scenario with stable signals, when the power amplifier is stable by itself, there is no need to introduce an RC stabilization network; in a scenario with unstable signals, when the power amplifier is unstable by itself, the RC stabilization network can be introduced to suppress high-frequency oscillations in the signals within a preset frequency band.

[0091] In the multi-band radio frequency power amplifier proposed in the embodiments of the present invention, the input matching network and the output matching network cooperate to ensure low-loss transmission of signals within multiple frequency bands or a wide frequency band. The gate and the multi-band drain bias circuit jointly set the working state of the FET, while the RC stabilization network ensures stability across the entire frequency band. Ultra-wideband output matching may sacrifice some efficiency in exchange for bandwidth and is suitable for application scenarios that need to cover multiple frequency bands simultaneously, while multi-passband input matching optimizes efficiency for specific frequency bands.

[0092] For the layout of a multi-band radio frequency power amplifier based on coupled lines provided in the embodiments of the present invention, please refer toFigure 2 As shown, it can be seen that the multi-band RF power amplifier may include: a multi-passband filter type input matching network composed of 9 microstrip lines TL1 - TL9 and 1 coupled microstrip line CL1; an ultra-wideband output matching network composed of 3 microstrip lines TL17 - TL19 and 1 DC-blocking patch capacitor C7; an RC stabilization network composed of 1 resistor R and 1 capacitor C3 in parallel; a multi-band gate bias circuit composed of 3 series-connected microstrip lines TL10 - TL12 and 2 patch capacitors C1, C2 connected to ground in parallel; a multi-band drain bias circuit composed of 4 series-connected microstrip lines TL13 - TL16 and three patch capacitors C4 - C6 connected to ground in parallel. The multi-band RF power amplifier has a total of four ports, RFin is the RF input port, RFout is the RF output port, Vgs is the gate DC voltage input port, and Vds is the drain DC voltage input port. The component values of the 4-band RF power amplifier based on coupled lines are: TL1.W / L = 4 / 10mm (W represents the width of this microstrip line, L represents the length of this microstrip line, TL1.W / L = 4 / 10mm means the width of microstrip line TL1 is 4mm and the length is 10mm), TL2.W / L = 3.8 / 17.8mm, TL3.W / L = 1.4 / 5mm, TL4.W / L = 3.8 / 17.5mm, TL5.W / L = 2.4 / 12mm, TL6.W / L = 0.5 / 7mm, TL7.W / L = 3.9 / 1.7mm, TL8.W / L = 0.8 / 3.7mm, TL9.W / L = 7 / 1.5mm, TL10.W / L = 0.5 / 2.5mm, TL11.W / L = 0.5 / 2mm, TL12.W / L = 0.5 / 16.9mm, TL13.W / L = 2 / 5mm, TL14.W / L = 2 / 5mm, TL15.W / L = 2 / 5mm, TL16.W / L = 2 / 5.9mm, TL17.W / L = 7 / 9.6mm, TL18.W / L = 4.9 / 5.9mm, TL19.W / L = 2.8 / 13.9mm, TL20.W / L = 4 / 5mm, CL1.W1 / W2 / S / L = 1.4 / 0.5 / 0.1 / 15.8mm (W1 represents the width of the main transmission line, W2 represents the width of the coupled line, S represents the coupled line spacing, L represents the coupled line length, CL1.W1 / W2 / S / L = 1.4 / 0.5 / 0.1 / 15.8mm means the width of the main transmission line of the coupled microstrip line CL1 is 1.4mm, the width of the coupled line is 0.5mm, the coupled line spacing is 0.1mm, and the coupled line length is 15.8mm), C1 = 100uF, C2 = 1uF, C3 = 2.4pF, C4 = 100uF, C5 = 1uF, C6 = 10pF, C7 = 10pF, R = 15Ω, Vgs = -2.8V, Vds = 28V.

[0093] In the embodiment of the present invention, the used board is Rogers4350B with a thickness of 0.762 mm. The four operating frequency bands are 0.7 - 0.8 GHz, 2.5 - 2.7 GHz, 3.5 - 3.7 GHz, and 4.8 - 5 GHz, and the center frequencies are 0.75 GHz, 2.6 GHz, 3.6 GHz, and 4.9 GHz respectively. The layout size can be 110 mm × 34.8 mm, the circuit area is small, and it has a small volume and high integration. Figure 3 It is the simulation curve graph of the return loss and small-signal gain of a multi-band RF power amplifier based on coupled lines provided by the embodiment of the present invention. Figures 4 - 7 They are respectively the output power, gain, and power added efficiency graphs of the center frequencies of the four frequency bands. From Figures 3 - 7 it can be seen that for the multi-band power amplifier based on coupled lines described in Embodiment 1 of the present invention, the four frequency bands are clearly visible, which are 0.7 - 0.8 GHz, 2.5 - 2.7 GHz, 3.5 - 3.7 GHz, and 4.8 - 5.0 GHz respectively. The simulated return loss is good within the four frequency bands. At 0.75 GHz, the gain is greater than 20 dB, and the saturated added efficiency is greater than 63%. At 2.6 GHz, the gain is greater than 16 dB, and the saturated added efficiency is greater than 62%. At 3.6 GHz, the gain is greater than 17 dB, and the saturated added efficiency is greater than 61%. At 4.9 GHz, the gain is greater than 15 dB, and the saturated added efficiency is greater than 60%.

[0094] The multi-band RF power amplifier provided by the embodiment of the present invention adopts a multi-passband filter type input matching network that can support multiple different operating frequencies simultaneously, without the need for multiple single-frequency power amplifiers to cooperate. This greatly reduces the circuit area and design and manufacturing costs, and improves the integration. In the traditional technology, the use of multiple single-frequency power amplifiers in cooperation will increase the interconnection loss between devices, resulting in performance attenuation of the output power and output efficiency. However, in the present invention, through an integrated design, the compatibility between different frequency bands is better, the circuit is simpler, and the loss is lower, which can ensure a higher output power and efficiency. Further, by utilizing the capacitive coupling characteristic of the coupled lines in the multi-passband filter type input matching network, a DC blocking capacitor can be not used in the input matching network, so the design complexity is lower.

[0095] It should be noted that in the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0096] The above are only the preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are all included in the protection scope of the present invention.

Claims

1. A multi-band radio frequency power amplifier based on coupled lines, characterized in that Comprising: A multi-passband filter type input matching network, a multi-band gate bias circuit, a field effect transistor, a multi-band drain bias circuit, and an ultra-wideband output matching network; wherein, The multi-passband filter type input matching network is used to screen the input signal, allow the signal within a preset frequency band to pass through, and perform impedance matching, and send the signal within the preset frequency band to the field effect transistor; The multi-band gate bias circuit is used to provide a gate DC bias voltage to the gate of the field effect transistor; The field effect transistor is used to amplify the signal within the preset frequency band and output the amplified signal; The multi-band drain bias circuit is used to provide a drain DC bias voltage to the drain of the field effect transistor; The ultra-wideband output matching network is used to perform impedance matching between the output end and the load and output the amplified signal.

2. The multi-band radio frequency power amplifier based on a coupled line according to claim 1, wherein The multi-passband filter type input matching network is formed by connecting a coupled line and M microstrip lines in series according to the operating frequency band, where M is a positive integer greater than or equal to 2. Among them, the input end of the multi-passband filter type input matching network serves as the input end of the multi-band radio frequency power amplifier.

3. A multi-band RF power amplifier based on coupled lines according to claim 1, characterized in that The multi-band gate bias circuit is formed by connecting Q microstrip lines in series, and a grounded capacitor is connected in parallel between adjacent microstrip lines, where Q is a positive integer greater than or equal to 2.

4. A multi-band RF power amplifier based on coupled lines according to claim 3, wherein, The input end of the multi-band gate bias circuit serves as the input end of the gate direct current of the multi-band radio frequency power amplifier, and the gate voltage Vgs is connected, and the output end is connected to the bias end of the multi-passband filter type input matching network.

5. The multi-band radio frequency power amplifier based on a coupled line according to claim 1, wherein The multi-band radio frequency power amplifier further includes: an RC stabilization network; the RC stabilization network suppresses the high-frequency oscillation in the signal within the preset frequency band and outputs the suppressed signal to the field effect transistor.

6. The multi-band RF power amplifier based on coupled lines according to claim 5, wherein, The RC stabilization network is composed of a resistor R and a capacitor C3 connected in parallel.

7. The multi-band radio frequency power amplifier based on coupled lines according to claim 1, characterized in that The source of the field effect transistor is grounded, the gate is connected to the output end of the multi-passband filter type input matching network, and the drain is respectively connected to the output end of the multi-band drain bias circuit and the input end of the ultra-wideband output matching network.

8. A multi-band radio frequency power amplifier based on coupled lines according to claim 1, wherein The multi-band drain bias circuit is formed by connecting X microstrip lines in series, and a grounded capacitor is connected in parallel between adjacent microstrip lines, where X is a positive integer greater than or equal to 2.

9. The multi-band RF power amplifier based on coupled lines according to claim 8, characterized in that, The input end of the multi-band drain bias circuit serves as the input end of the drain direct current of the multi-band radio frequency power amplifier, and the drain voltage Vds is connected, and the output end is connected to the drain of the field effect transistor.

10. A multi-band radio frequency power amplifier based on coupled lines according to claim 1, characterized in that, The ultra-wideband output matching network is formed by connecting P microstrip lines and a capacitor C7 in series, where P is a positive integer greater than or equal to 2.

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